Two Houses, One Law
About 40% of the world's national parliaments are split into two separate chambers. This setup is called bicameralism. It shrank in the early 20th century, but it has grown a lot since the 1970s. The other 60% of countries use unicameralism, where every member sits and votes as one group.
The two chambers are often filled in very different ways. One might be elected by the public, while the other is appointed or chosen by regional governments. That can give the two houses very different kinds of members.
Passing a major law often needs a concurrent majority, meaning a majority in each house. Supporters say this gives useful checks and balances that stop rushed laws. Critics say it makes real reform harder and raises the risk of gridlock, especially when both houses have similar powers.
From Medieval England to the US Senate
British bicameralism goes back to 1341. That year, the Commons met apart from the nobles for the first time, creating an upper and a lower chamber. From 1544, the upper one was known as the House of Lords. Britain's Parliament is often called the "Mother of Parliaments", but that is a misquote. In 1865, John Bright actually said that "England is the Mother of Parliaments".
The founders of the United States also wanted two houses. They planned the Senate as a calm, steady force against what James Madison saw as the "fickleness and passion" of the House. At first, state lawmakers picked the senators. That lasted until 1913, when the 17th Amendment made senators elected by popular vote.
The Connecticut Compromise added a clever twist. Every state got exactly two senators, no matter its size, while seats in the House followed population.
The Washminster Mutation
Australia mixed the British Westminster tradition with ideas from the US Constitution. Many political scientists see it as a deliberate blend of the two, and the blend earned a nickname: "the Washminster mutation".
The lower house had 151 members as of 2017. The Senate has 76: 12 from each of the 6 states, no matter their population, plus 2 from each of the 2 territories. Senators are elected using proportional representation, so the chamber is full of different parties. Unlike most upper houses in Westminster systems, it can block the government's laws. The governing party rarely controls it, so it usually has to bargain with smaller parties and independents.
Canada went another way. Its senators are appointed and serve until age 75. The elected House of Commons is clearly in charge. The Senate works mostly as a chamber of revision: it rarely rejects bills, but it often amends them, and the Commons usually accepts the changes.
Seats by Family Title, Votes by State
Britain's House of Lords is the best known upper house with aristocratic roots. Some members are hereditary peers, who hold their place through a family title. In 1999, a new law cut their number from around 700 to just 92. In 2021, 803 people sat in the House of Lords, and its size only shrinks when members retire, resign or die. Until 2009, 12 senior judges even sat in the house as the country's highest court.
Germany does things differently. Members of its Bundesrat are chosen by the state governments, and each state gets between three and six votes. The biggest state has about 27 times the people of the smallest, so small states get far more weight than their population alone would give them.
There is a twist. German legal thinking does not treat the Bundesrat as a true second chamber at all. Only the directly elected Bundestag counts as the parliament.
When the Two Houses Can't Agree
Sometimes the two houses simply disagree. Britain once settled this with "free conferences", where managers from both houses met in private. The last one at Westminster was held in 1836, and the one before that was way back in 1740. In 2011, the lower house of New South Wales in Australia asked for a free conference over a bill on graffiti. After a year, the upper house said no, calling the method archaic.
The United States uses a conference committee, a small group from both chambers that settles on one final wording. In the 1930s, Nebraska cut its legislature down to a single chamber, partly to get rid of that process.
Others have gone the same way. The German state of Bavaria abolished its Senate by referendum in 1999. In Romania, 77.78% of voters backed a single chamber in a 2009 referendum, but that vote was only advisory.
